Water supply is a key consideration in sustainable urban planning. Recycling may increase the expense and energy consumption of supply systems, raising optimisation questions. Ideally, detailed quantitative sustainability assessments are undertaken during the planning stage in order to inform the decision-making process. In reality, however, the significant time and cost associated with undertaking such detailed environmental and economic assessments is often cited as a barrier to wider implementation of these key decision-support tools, particularly for decisions made at the local or regional government level. In an attempt to counter this barrier of complexity, four water service providers in Melbourne (Australia) funded the development of a publicly available streamlined Environmental Sustainability Assessment Tool (ESAT). The tool is aimed at a wide range of decision-makers to assist them in broadening the type and number of water servicing options that can be considered for greenfield or backlog developments. ESAT consists of a simple user interface and draws upon life cycle inventory data to allow for rapid estimation of the environmental and economic performance of different water servicing scenarios. Scenario options can then be further prioritised by means of an interactive multicriteria analysis. The intent of this paper is to identify the key issues to be considered in a streamlined sustainability assessment tool for the urban water industry and to demonstrate the feasibility of generating accurate life cycle assessments (LCAs) and life cycle costings (LCCs) using such a tool. We use a real-life case study consisting of three separate scenarios for a planned urban development to show that this kind of tool can emulate LCA and LCC outcomes obtained by more detailed studies. We hope this kind of approach will support ‘sustainability thinking’ early on in the decision-making process, thereby encouraging more sustainable water and sewerage infrastructure solutions.